Vulcanized glycerol resin.



No Drawing.

onITED STATES PATENT OFFICE.

c. ABSEM,

6F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, .A.CORPORATION OF NEW YORK.

, VULCANIZED GLYCEROL RESIN.

Specification of Letters Patent.

Patented Dec. 23, 1913.

Application filed March 8. 1913. Serial No. 752,977.

' Glycerol Resin, of whichthe following is a specification.

The present invention comprises a new synthetic rubber-like material andthe process of making the same.

I have discovered that when a mixed ester ofv glycerol, orotherpolyhydric alcohol, and of both a saturated and an unsaturatedorganic acid, is acted upon by sulfur, that a rubbery, infusible mass isformed which can be used for many purposes to replace rubber.

In the preferred form of my invention the mixed esteris prepared asfollows: An ester containing free hydroxyl groups is first prepared bheating glycerol and phthalic anhydrid to' a reactlon temperature, sayabout 200 to 210 0., until gas bubbles cease arising. I prefer to usemolecular proportions, these corresponding by weight with about 92 partsof glycerol and 148 parts of phthalic anhydrid butin some 7 cases I mayuse less phthalic' anhydrid and more of the unsaturated acid which issubsequently added. At this stage of the reaction some thickening takesplace but it should be interrupted before a jelly-like mass forms. Tothe resulting mass one molecular proportion, or 282 parts by weight ofoleic acid is added and heating resumed. Gas and steam are again formedand at 192 to 195 C. the bottom layer of resin becomes opaque.Aftercontinued heating at about 210 to 215 C. the resin and the oleicacid will mix to form a mixture having a deep red color. The temperatureshould be maintained below 230 C. as considerable frothing will occur ifit rises above this point. Care should be taken to prevent this byagitating the mixture and regulating the heat and if this is done agentle reaction will go on which is completedv after several hours. Theresin at this stage isa viscous red liquid. This resin is described andclaimed in a co pending application, Serial I No.

781,111, filed July 25, 1913. About 20 parts of finely divided sulfurare now added to the resin and thoroughly distributed by stirring. Theheating is then resumed with continual stirring until reaction occurs. Adark, brown elastic mass having a faint rubher-like odor is formed. Theproportion of sulfur may be varied considerably and may be as low as 10%and as high as 30%.

In some cases substances such as castor oil or pitch may to advantage beadded to the glycerol resin and this mixture treated with sulfur asabove described. To 100 parts of the glycerol resin of oleic andphthalic acid, about 1 to 10 parts of either castor oil or pitch isadded and the mixture is then acted upon with 10 to 80 parts of sulfur.These additions modify the consistency and elasticity of the product. Ifind that mechanical kneading or working is also beneficial to improvethe mechanicalproducts of the rubber-like, compound.

The final product is infusible, will stand 200 C. without apparentchange, but when heated, strongly decomposes andchars like rubber. It isattacked somewhat byxylene, benzene, but is otherwise insoluble inordinary solvents. When used for the production of molded compounds itmay be mixed with a filler such as talc, zinc oxid, finely powderedsilica or other inert material, and in some cases a certain amount ofground rubber may also be added. The material is substantially equal torubber for various uses, for example, stoppers, erasers, pads, Washers,insulation, molded materials and the like. Equivalent amounts of otherunsaturated acid such as cinnamic acid may be used to replace the oleicacid inepart or entirely. In the same manner glycerol may be replaced byits polymers.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. The process which consists in heating a mixed glycerol ester ofphthalic anhydrid comprising a compound of sulfur and the glycerol esterof phthalic and oleic acids.

6. A rubber-like compound of an ester of phthalic and oleic'acids, andsulfur.

In Witness whereof, I have hereunto set 15 my hand this 6th day ofMarch, 1913. 4 WILLIAM C. ARSEM. Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

